Kazumi Ida, a high school student, plunges into the world of magic after his best friend Takeshi Nanase transforms into a magician. During a clash between Takeshi and the Ghost Trailers organization, Kazumi absorbs stray magic through Hotaru Kumagai's influence, unknowingly becoming a magician himself. His hand catches fire shortly after, causing panic before he masters control. He transfers to Subaru Magic Academy with Takeshi and their childhood friend Kurumi Isoshima to train.

Kazumi cultivates a delinquent image with bleached blonde spiky hair, his school uniform unbuttoned to show a red undershirt, earrings, and a distinctive skull ring serving as his magical Aspect. He speaks in a thick Osaka dialect. Despite this intimidating exterior, his personality is fundamentally loyal and softhearted, especially towards Takeshi. This stems from Takeshi protecting Kazumi's younger sister Futaba from a threatening older man, an event that forged Kazumi's deep gratitude and sense of debt.

Kazumi harbors a strong, often overbearing protective instinct toward Futaba. An argument about her travel plans with male classmates triggers his uncontrolled magic, accidentally transforming her into a magician. He enrolls her at Subaru Academy, closely monitoring her activities. When Ghost Trailers attack the academy, Kazumi prioritizes finding Futaba but suffers severe injuries witnessing her abduction. Scarred but resolute, he remains with Takeshi to train for her rescue.

His magic focuses on Destruction, specializing in fire manipulation and explosive force. Key spells include the fire-channeling Blast Finger (activated by a gun-shaped hand gesture), the speed-enhancing Drive, the defensive barrier Protect, and the levitation/magic-amplifying Liberate. In combat, he frequently collaborates with Takeshi, infusing fire into Takeshi's sword-projectiles for enhanced attacks. During the mission to rescue Kurumi from Ghost Trailers, Kazumi confronts Hotaru alongside Mui Aiba. After initial struggle, he reveals he held back and defeats Hotaru decisively using Blast Finger.

Relationships significantly shape him. His foundational bond with Takeshi is marked by unwavering loyalty and combat synergy. Kurumi is often annoyed by his behavior, which he doesn't take personally. His dynamic with Futaba reflects deep care, though his excessive protectiveness strains their relationship.

Following Futaba's kidnapping, Kazumi's singular focus becomes her rescue. He accompanies Takeshi and Mui to Ghost Trailers' headquarters, battling key members. His combat effectiveness increases as he demonstrates greater power control and strategic restraint.